This invention relates to methods for delivering and deploying modular sections of an endovascular stent/graft for assembly thereof within the vasculature of a patient and specifically to a system for accomplishing the same.
It is well established that various fluid conducting body or corporeal lumens, such as veins and arteries, may deteriorate or suffer trauma so that repair is necessary. For example, various types of aneurysms or other deteriorative diseases may effect the ability of the lumen to conduct fluids and, in turn, may be life threatening. In some cases, the damage to the lumen is repairable only with the use of prosthesis such as an artificial vessel or graft.
For repair of vital lumens such as the aorta, surgical repair is significantly life threatening or subject to significant morbidity. Surgical techniques known in the art involve major surgery in which a graft resembling the natural vessel is spliced into the diseased or obstructed section of the natural vessel. Known procedures include surgically removing the damaged or diseased portion of the vessel and inserting an artificial or donor graft portion inserted and stitched to the ends of the vessel which were created by the removal of the diseased portion. More recently, devices have been developed for treating diseased vasculature through intraluminal repair. Rather than removing the diseased portion of the vasculature, the art has taught bypassing the diseased portion with a prosthesis and implanting the prosthesis within the vasculature. An intra arterial prosthesis of this type has two components: a flexible conduit, the graft, and the expandable framework, the stent (or stents). Such a prosthesis is called an endovascular graft.
It has been found that many abdominal aortic aneurysms extend to the aortic bifurcation. Accordingly, a majority of cases of endovascular aneurysm repair employ a graft having a bifurcated shape with a trunk portion and two limbs, each limb extending into separate branches of vasculature. Currently available bifurcated endovascular grafts fall into two categories. One category of grafts are those in which a preformed graft is inserted whole into the arterial system and manipulated into position about the area to be treated. This is a unibody graft. The other category of endovascular grafts are those in which a graft is assembled in-situ from two or more endovascular graft components. This latter endovascular graft is referred to as a modular endovascular graft. Because a modular endovascular graft facilitates greater versatility of matching individual components to the dimensions of the patient's anatomy, the art has taught the use of modular endovascular grafts in order to minimize difficulties encountered with insertion of the devices into vasculature and sizing to the patient's vasculature.
Although the use of modular endovascular grafts minimize some of the difficulties, there are still drawbacks associated with the current methods. Drawbacks with current methods can be categorized in three ways; drawbacks associated with delivery and deployment of the individual endovascular graft components, drawbacks associated with the main body portion, and drawbacks associated with securing the limb portions to the main body portion.
Certain of the grafting apparatus for modular graft systems lack sufficient control of the deployment of self-expanding graft devices. While relying upon pusher assemblies to simply eject the graft devices from within a delivery sheath, precise positioning of the graft device is sometimes not accomplished. Such systems often lack subassemblies which facilitate the controlled delivery of modular, self-expanding graft devices which has been removed from a delivery sheath.
Additionally, certain of the available modular graft devices rely upon frictional engagement to ensure a graft-to-graft assembly of modular components. Other devices merely contemplate fully deploying a main graft component of a modular system and thereafter deploying subsequent graft components within a limited docking site, thereby resulting in a less adjustable assembly more concerned with precise assembly of graft components than compensating for a patient's anatomy.
There therefore exists a need for an endovascular graft delivery system that can be easily operated by a single technician without decreased reliability or additional risk to the patient. Additionally, a need exists for a delivery system that provides enhanced control of the delivery of self-expanding graft components of a modular design. Modular graft components including attachment systems that accomplish secure junctions are also needed as are graft support structures providing a reliable access to graft-to-graft junctions and enhanced ability to conform to patient anatomy.
The devices and methods of the present invention addresses these and other needs.